It has a protective function. If the voltage and current of the original mobile phone is the same as that of other mobile phones, there is no problem in charging (it does not matter if the current is large, but the charging is slow and the charger is easy to break), if it is the charger of other assembled or shanzhai high imitation charger, the charging problem is not big, but the stability and internal insulation performance may not be as good as the original. There may be safety hazards in areas where the mains supply is not stable.